Septic Tank Size Calculator
Tank capacity for your household.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Recommended tank size
- 1,000 gallons
- Daily wastewater flow
- 280 gallons
- Minimum by bedroom count
- 1,000 gallons
- Retention time target
- 48 hours minimum
- Pump-out interval estimate
- 0.5 years
Quick answer
Most codes require at least 1000 gallons for a three bedroom home, rising with bedroom count and daily flow.
How to use the Septic Tank Size Calculator
- 1Enter the number of bedrooms — most codes size on this.
- 2Enter actual occupants and water use.
- 3Use the larger of the two figures.
Frequently asked questions
How often should I pump?
Every 3–5 years for a typical family of four.
Does a garbage disposal matter?
Yes — it adds solids, so consider a larger tank.